Mineral nutrition of the wheat plant in relation to its development

The yield and chemical composition of a plant are augmented by the effect of biochemical processes occurring within the plant. The direction of these processes depends on the biological nature of the plant itself and the environment. Mineral fertilizers are one of the factors of the environment which govern the growth and development of the plant. For maximum crop yield will depend upon the understanding of the mode of interaction of the various environmental factors - water supply, spacing, sowing date, nutrient supply and the climatic factors. The economics of wheat production demands, on the one hand, a sizeable yield, and on the other, high grain quality. The baking quality of flour depends largely on the amount of protein present in the grain. Improvements of both factors have been sought through plant breeding, but sound management is equally important incorporating scientific and economic principles for the production of optimal crops. Overseas work has thrown some light on the crop’s response to fertilizers, though detailed work pertaining to the physiological aspects of grain yield in New Zealand is not considerable. In wheat growing areas where little if any nitrogen is applied to wheat, as in New Zealand, the dependence on nitrogen for growth is basically on the rate of mineralization of soil organic matter. Its rate determines the amount of nitrogen available during growth after allowance is made for losses through leaching, microbial activity and gaseous losses. For the completion of growth, the plant will depend on its ability to take up the available soil nitrogen and redistribute it during growth. Under conditions of nitrogen stress at later stages of growth completion of plant growth will, to a large measure, depend on plant nitrogen taken up during early growth. An experiment was conducted with the variety Hilgendorf (1961) to study the uptake and utilization of nitrogen throughout growth particularly with respect to the effect of raising the nitrogen level at different times on plant growth, yield and grain quality. It was anticipated that the investigation would reveal some knowledge on the dependence for inflorescence nitrogen on uptake and on redistribution within the plant. While the experiment was conducted under partially controlled conditions, as in the glasshouse, it is envisaged that the study of the physiological behaviour of Hilgendorf (1961) will enlighten the behaviour of other Hilgendorf strains of wheat